Torsion spring dampers are known. Examples are shown in U.S. Pat. No. 4,181,208 to Davis, U.S. Pat. No. 4,795,012 to Durum, and U.S. Pat. No. 5,234,376 to Chimner et al. A turbine mass absorber is described in commonly-assigned United States Patent Application Publication No. 2009/0125202 to Swank et al., hereby incorporated by reference as if set forth fully herein. In an example embodiment of the Swank publication, the turbine mass absorber includes an elastic member with a linear zero torque transmission.